Search

Melanocytic matricoma is a rarely reported, benign cutaneous adnexal neoplasm composed of epithelial cells exhibiting differentiation towards hair matrix as well as admixed, pigmented, dendritic melanocytes. The proposed malignant counterpart to melanocytic matricoma, malignant melanocytic matricoma (MMM), is even more rare. Here we report a case of a melanocytic matricoma with atypical features in a 92-year-old female with a 1.2-cm pigmented nodule on the right nasal sidewall. Histopathology revealed a well-circumscribed dermal tumor composed of atypical matrical cells with scattered aggregates of anucleate keratinocytes (ghost cells), prominent intratumoral pigment, numerous mitotic figures (88 mitosis/10 high-power field [HPF]), and intermixed dendritic melanocytes. A literature review was performed for MMM to determine if the current case fit diagnostic criteria for this entity. Including the current case, 12 cases of MMM were identified and analyzed to investigate common clinical and histopathologic features. MMM commonly occurred on the head and neck (7/12 cases) of older individuals (median age of 80) with a slight male predominance (male-to-female ratio of 3:1) and on histopathology presented as a multinodular dermal tumor composed of mitotically active (average mitotic rate of >50 mitoses/10 HPF) pleomorphic epithelial cells with foci of ghost cells. Dendritic melanocytes were found throughout the tumor lobules in all cases. Given that only two of 12 cases have exhibited locally aggressive behavior, further study is warranted to determine the true malignant potential of MMM., (© 2022 Japanese Dermatological Association.)

A 23-year-old man presenting with a 1-year history of a lesion of the right cheek. We highlight this case for awareness as this tumour may mimic other benign lesions, such as pilomatrixoma or benign cysts, as it does not have any uniquely identifying clinical or dermoscopic features. Additionally, it is of concern as malignant transformation can occur and therefore surgery should be considered as both for diagnostic and therapeutic benefit., (© 2022 British Association of Dermatologists.)

Abstract: Trichilemmoma is a benign cutaneous neoplasm that recapitulates the outer root sheath of the hair follicle. Trichilemmomas may occur sporadically or in association with Cowden syndrome, which is characterized by germline mutations in the lipid phosphatase PTEN (phosphatase and tensin homolog on chromosome 10). Interestingly, most sporadic trichilemmomas do not show PTEN aberrations, but rather activating mutations in HRAS. Despite these important advances, a comprehensive genetic analysis of trichilemmoma has not been reported. Here, we used a next-generation DNA sequencing platform to study 9 sporadic trichilemmoma cases. Seven cases (7/9; 78%) harbored activating mutations in HRAS, consistent with previous findings. Unexpectedly, we identified recurrent mutations in the tyrosine phosphatase PTPN14 (protein tyrosine phosphatase nonreceptor type 14) in 4 cases (4/9; 44%). Three of these cases also harbored HRAS mutations, whereas one case occurred in the absence of a HRAS mutation and showed evidence of biallelic inactivation of PTPN14. Finally, one case (1/9; 11%) showed biallelic inactivation of PTEN in the absence of a HRAS (or PTPN14) mutation. These data suggest at least 3 distinct pathways of molecular pathogenesis in sporadic trichilemmoma and identify PTPN14 as a potentially important contributor to trichilemmoma biology., Competing Interests: J. Hanna has disclosed that he is a recipient of research funding from the Bertarelli Rare Cancers Fund. Lippincott CME Institute has identified and resolved all conflicts of interest concerning this educational activity., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

Purpose: To analyze the histopathological changes in eyelash following electroepilation using radiofrequency (RF) cautery., Methods: RF current was applied to the eyelash root in human eyelids (from exenteration or eyelid shortening procedures) at a pre-determined depth of 3 mm excision a-priori, and processed for routine histology. Studied parameters were the extent of necrosis, involvement of the eyelash bulb, and type of bulb damage (partial or whole necrosis). Also, seven patients of chronic cicatrizing conjunctivitis with trichiasis ( n  = 4) and distichiasis ( n  = 3) underwent electroepilation using the above RF protocol., Results: Twelve eyelid specimens of seven patients (mean age 40 years; five upper eyelid and seven lower eyelid) were evaluated histologically. Majority of specimens (92%) showed coagulative necrosis in the eyelash bulb, follicle, orbicularis oculi, adjacent nerves, and blood vessels. The mean depth of necrosis was 2.12 ± 0.63 mm. Of 12, eleven eyelash bulbs showed necrotic changes with only partial bulb involvement in 55% of eyelids. The horizontal extent of coagulative necrosis was not uniform across the lash track, and the majority showed a wider area of damage in the lower segment. Of seven, all patients with trichiasis (4/4) showed no recurrence of lash misdirection whereas 66% of distichiasis patients (2/3) showed recurrent lash growth with one sitting of electroepilation applied at 3 mm., Conclusions: Electroepilation guided by RF current produces variable necrotic changes in the eyelash root, leaving portions of intact bulbs in half of the eyelids.

Pilomatricomas are benign skin tumors often encountered by otolaryngologists but frequently misdiagnosed. Although they can occur at any age, they commonly present in children as a discolored superficial lesion adhered to the overlying skin. Accurate preoperative diagnosis is crucial for appropriate management, which is surgical in most cases. Here, we present bilateral pilomatricomas mimicking features of several other diagnoses in a pediatric patient. The patient was successfully treated with surgical excision. This case presented a unique diagnostic challenge, as the lesions exhibited features of several common diagnoses. In general, surgical management of pilomatricoma is curative, and recurrence is rare.

Trichoblastic carcinoma is a rare neoplasm thought to arise from malignant degeneration of benign follicular tumors. Its clinical features, optimal treatment, and outcomes remain largely unknown. We performed a comprehensive review of the existing trichoblastic carcinoma literature. PubMed and Google Scholar were searched for keywords related to trichoblastic carcinoma, and additional articles were found in reference lists. Cases with a histopathologic diagnosis of trichoblastic carcinoma were summarized. A total of 93 cases have been described, all in case reports or case series. The average age was 65, with 66.7% of cases in males. A minority of patients had familial tumor syndromes or a history of radiation at the site, and only one was reported to be immunosuppressed. The most common site was the face (48.4%), and the majority developed de novo (87.1%). The clinical presentation was highly variable. Although most cases (82.8%) were successfully treated with surgery alone, a subset of patients had more aggressive disease including local progression or recurrence in five cases, nodal metastases in five cases, and distant metastases in three cases. Trichoblastic carcinoma is a rare malignancy with the potential for aggressive behavior. Further research is needed to better characterize this neoplasm., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Abstract: Pilomatrical differentiation can be observed in a variety of benign and malignant tumors, with the most common prototype being pilomatricoma. Pilomatricoma often presents in the deep dermis or subcutis, and the sole involvement of epidermis is extremely rare. In our current case series, specimens from 5 patients were included with an average age of 68 years. All lesions presented as solitary verrucous or keratotic papules on the extremities, with 1 lesion having a prominent horn. All lesions have a variable mixture of basaloid matrical cells and shadow cells, and all lesions express β-catenin (strong nuclear and cytoplasmic), lymphoid enhancer-binding factor 1 within the matrical component, and pleckstrin homology-like domain family A member 1. The histomorphology and immunoprofile of all lesions are of pilomatrical differentiation, confined to the level of the epidermis. Based on these findings and analogous to the terminology used for other benign intraepidermal proliferations (hidroacanthoma simplex and epidermolytic acanthoma), we propose the term "pilomatrical acanthoma" for these rare lesions., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

Uncombable hair syndrome presents with frizzy hair in early childhood. Isolated hair manifestations are usually observed; however, systemic involvement of the nervous system, eyes, and ears have also been reported. The syndrome has been classified into three subtypes, correlating with the three mutated genes: peptidyl arginine deiminase, type III; transglutaminase 3; and trichohyalin. This article presents the clinical picture of uncombable hair syndrome with special attention to its systemic manifestations. It also addresses its molecular aspects. Google Scholar was used to retrieve relevant publications. Clinical and molecular data were tabulated and frequencies were calculated. At least 127 cases were identified. Congenital hair defects were reported in two-thirds of cases, in which hair texture (83%), color (52%), density (15%), and growth (11%) were impaired. Uncombable hair rarely involves the eyebrows and eyelashes, and it may co-occur with loose anagen hair syndrome, androgenic alopecia, alopecia areata, and scarring alopecia. Pathologies of the skin, nails, and teeth were reported among 63%, 28%, and 25%, respectively. Systemic abnormalities were not uncommon. Dysmorphic features (n = 8), and neuropsychiatric/developmental (n = 8), ophthalmic (n = 7), otic (n = 4), and cardiopulmonary (n = 3) manifestations were also reported. Molecular genetic analysis of all patients is recommended to identify genotype-phenotype correlation. A general pediatric review might be needed to rule out any potential systemic association.

Abstract: Panfolliculomas (PF) are rare, benign, follicular tumors that differentiate toward multiple components of the hair follicle, and several variants have been described. We present a case of a rare pigmented PF presenting on actinically damaged skin in an 83-year-old man, which was clinically concerning for malignancy. This tumor arose near an area of atypical squamous proliferation and has evidence of infundibular, outer root sheath, and matrical differentiation and foci of heavy melanin pigmentation and increased melanocytes. We propose the novel designation of "melanocytic PF," akin to melanocytic matricoma but with panfollicular differentiation., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)

Collision tumours are a random association of two or more neoplasms arising in the same anatomical site. Dilated pore of Winer (DPW) - an adnexal tumour of pilar origin - has been described in collisions with basal cell carcinoma (BCC), squamous cell carcinoma (SCC) and trichoblastoma. We present a literature review of melanoma-associated skin lesions and describe the first collision of a DPW with a melanoma in situ (MIS) and the sequential dermoscopic examination for diagnosis., (© 2021 The Australasian College of Dermatologists.)

Abstract: Basaloid follicular hamartoma (BFH) is a rare, benign follicular neoplasm which typically presents as brown to skin-colored papules on the face, scalp, and trunk. Histologically, BFH consists of cords and strands of basaloid cells forming cystic structures with scant stroma and should be distinguished from infundibulocystic basal cell carcinoma to avoid overly aggressive treatment. Although BFH has been found to be associated with distinct syndromes, including alopecia, myasthenia gravis, and cystic fibrosis, there is often clinical, histopathologic, and genetic overlap with nevoid basal cell carcinoma syndrome (NBCCS). In this article, we describe a case of a 13-year-old patient with NBCCS who presented with multiple BFHs and propose that it its inclusion into the diagnostic criteria for NBCCS be considered., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)

Background: Skin adnexal tumours (SATs) comprise a diverse range of neoplasms, which are difficult to diagnose clinically. They present in paediatric and adult populations, and may be indicative of an underlying genetic syndrome. There is a lack of recent data on the presentation of these tumours in clinical practice in European populations., Objectives: To characterize the clinical and pathological features of SATs received at a single tertiary centre over a 5-year period., Methods: A retrospective health record audit of SATs received at the Department of Cellular Pathology, Royal Victoria Infirmary, Newcastle upon Tyne Hospitals NHS Foundation Trust, during the period November 2012 to October 2017 was performed., Results: In total, 107 144 skin cases were received during the audit period. A total of 1615 cases of SATs from 1359 patients were included; 1570 (97·2%) were benign and 45 (2·8%) were malignant. Overall, the average age at presentation was 55 years (range 11 months to 97 years) and the male to female ratio was 0·77 : 1. Sweat gland and hair follicle SATs were most frequently excised; in adults, the most frequent tumour was hidrocystoma, and in children, pilomatrixoma occurred most often. Prebiopsy diagnosis was correct in 28% of cases. Benign SATs are often markers of an associated genetic condition, which warrants improved discrimination of sporadic from genetically related SATs., Conclusions: SATs are difficult to diagnose clinically, and clinicopathological correlation may help enhance discrimination of genetically related SATs from sporadic cases. These data have implications for clinical and dermatopathological training provision, the development of reporting standards, and genetic assessment of selected patients., (© 2021 British Association of Dermatologists.)

Background: Hair microscopy is a fast and effortless diagnostic method for many diseases affecting hair in daily practice. Many diseases can present with hair shaft disorders in pediatric neurology practice., Methods: Children with pathological hair findings were included in our study. Microscopic evaluation of the hair was performed under light microscopy. The clinical findings, pathological hair shaft findings, laboratory tests, and final diagnosis of the patients were evaluated., Results: In our study, 16 patients with rare pathological hair findings were identified. Of these 16 patients, nine were diagnosed with giant axonal neuropathy, three with Griscelli syndrome, two with Menkes disease, and two with autosomal recessive woolly hair disease. In hair inspection, curly and tangled hair in patients with giant axonal neuropathy; silvery blond hair in patients with Griscelli syndrome; sparse, coarse, and light-colored hair in patients with Menkes disease; and hypotrichosis in patients with autosomal recessive woolly hair were remarkable findings. Dystrophic hair was detected in most of the patients on light microscopy. In addition, signs of trichorrhexis nodosa, tricoptylosis, and pili torti were found. In particular, pigment deposition in the hair shaft of two patients diagnosed with Griscelli syndrome and pili torti findings in two patients with Menkes disease were the most important findings suggestingthe diagnosis., Conclusions: Detection of hair findings in the physical examination and performing light microscopic evaluation facilitates the diagnosis of rare diseases accompanied by hair findings. A hair examination should be performed as a part of physical and neurological examinationson eachpatient regardless of thecomplaint.

Investigations of hereditary phenotypes in spontaneous mutants may help to better understand the physiological functions of the altered genes. We investigated two unrelated domestic shorthair cats with bulbous swellings of the hair shafts. The clinical, histopathological, and ultrastructural features were similar to those in mice with lanceolate hair phenotype caused by loss-of-function variants in Dsg4 encoding desmoglein 4. We sequenced the genomes from both affected cats and compared the data of each affected cat to 61 control genomes. A search for private homozygous variants in the DSG4 candidate gene revealed independent frameshift variants in each case, c.76del or p.Ile26fsLeu*4 in case no. 1 and c.1777del or p.His593Thrfs*23 in case no. 2. DSG4 is a transmembrane glycoprotein located primarily in the extracellular part of desmosomes, a complex of adhesion molecules responsible for connecting the keratin intermediate filaments of neighbouring epithelial cells. Desmosomes are essential for normal hair shaft formation. Both identified DSG4 variants in the affected cats lead to premature stop codons and truncate major parts of the open-reading frame. We assume that this leads to a complete loss of DSG4 function, resulting in an incorrect formation of the desmosomes and causing the development of defective hair shafts. Together with the knowledge on the effects of DSG4 variants in other species, our data suggest that the identified DSG4 variants cause the hair shaft dystrophy. To the best of our knowledge, this study represents the first report of pathogenic DSG4 variants in domestic animals., (© 2021. The Author(s).)

Abstract: Trichoblastoma (TB) is a benign biphasic follicular neoplasm with differentiation toward the germinative cells and a specific follicular mesenchyme. We subtyped 349 sporadic TB according to a classification proposed by Ackerman. Two hundred forty-six (246/349, 70.5%) neoplasms were comprised of mixed subtypes. TB composed exclusively of a single pattern was less common (103/349, 29.5%). The most common pure subtype was cribriform TB followed by small nodular TB. Twelve cases (12/349, 3.4%) had unique features and are reported herein as novel histopathologic subtypes of the neoplasm., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)

Trichohepatoenteric syndrome (THES) is a very rare autosomal recessive genetic disorder, which is characterized by intractable diarrhea during infancy, dysmorphic features, immunodeficiency, and a failure to thrive. There are still significant difficulties for patients and clinicians in terms of the management of THES, even though its molecular basis has been uncovered in the last decade. In this article, we have presented two cases relating to siblings that have been diagnosed with the condition. Concerning one of the patients, we described a novel variation (c.2114 + 5G > A) in the TTC37 gene and a mild clinical course; meanwhile, the other one was clinically diagnosed with THES at 17 years of age, but they had seizures and died suddenly. These cases expand the spectrum of clinical findings in relation to THES., (© 2021 Wiley Periodicals LLC.)

Pilomatrix carcinoma (PC) is a rare malignant variant of pilomatrixoma, a skin adnexal tumor originating from hair matrix cells. It is most often located in the head, neck region, upper back and upper extremities. PC has a locally aggressive behavior but metastasis only occur in 10% of cases. Mutations in CTNNB1, the encoding gene of beta-catenin, have been found in both pilomatrixoma and PC, but other molecular alterations are unknown. The authors present a case of PC in the clitoris, the third known reported case located on the external genitalia. The tumor followed an unusual clinical course with the development of multiple metastases. Next-generation sequencing analysis of the tumor identified, in addition to a characteristic CTNNB1 mutation, pathogenic mutations in PTEN, PIK3CA, and ARID1A, which could explain the aggressive course of the disease. The diagnostic criteria of PC and the differential diagnoses of this unusual tumor in the genital area are discussed., Competing Interests: The authors declare no conflict of interest., (Copyright © 2020 by the International Society of Gynecological Pathologists.)

Aims: Trichoblastic carcinomas (malignant trichoblastomas) are rare and poorly documented neoplasms characterised by malignant transformation of a pre-existing benign trichoblastoma, and are subdivided histologically into low-grade and high-grade tumours. Whereas morphologically low-grade trichoblastic carcinomas show indolent behaviour, morphologically high-grade trichoblastic carcinomas have been associated with a poor prognosis, but little is known about their true biological potential. The aim of this study was to better define the clinicopathological features and outcomes of morphologically high-grade trichoblastic carcinomas., Methods and Results: Four high-grade trichoblastic carcinomas were retrieved from departmental files, and the clinical and histopathological features and follow-up were recorded. The tumours presented as nodules on the scalps, necks and shoulders of adults (median age, 40 years; range, 30-55 years) with a female predominance of 3:1. Three patients had a longstanding history with recent change. Histologically, three tumours were characterised by an expansile cellular nodule composed of sheets of pleomorphic epithelioid cells with brisk mitotic activity and necrosis arising in a background of a benign trichoblastoma. One tumour showed a more gradual transition from a benign trichoepithelioma to an undifferentiated carcinoma with infiltrative growth and perineural infiltration. All patients were alive with no evidence of recurrence or metastasis following complete excision after a median follow-up of 96 months (range, 30-180 months)., Conclusions: The correct diagnosis of high-grade trichoblastic carcinoma relies on adequate sampling and recognition of the benign trichoblastic precursor lesion, i.e. trichoblastoma or trichoepithelioma. Despite the concerning histological features of the malignant component, the tumours appear to be less aggressive than previously thought., (© 2021 John Wiley & Sons Ltd.)

Background: Ultra high-frequency ultrasound (uHFUS) is a recently developed diagnostic technology. Despite its potential usefulness, no study has assessed its advantage in diagnosis and evaluation of hair disorders in comparison with other diagnostic methods., Objectives: To assess the practicability of uHFUS in diagnosing hair disorders and propose a diagnostic methodology., Methods: Ultrasonographic images of scalp and forehead from patients with hair disorders (n = 103) and healthy controls (n = 40) were obtained by uHFUS and analyzed by both descriptive and numerical parameters. Furthermore, the data were compared with trichoscopic and histopathological findings., Results: The pattern of inflammation and fibrosis, hair cycle abnormality, and the findings in subcutis were detected by uHFUS. Significant differences were noted in the numerical parameters associated with the number of hair shafts and follicles, hair diameters and their diversity, and dermal echogenicity in both cicatricial and non-cicatricial hair disorders. Findings in uHFUS were associated with those observed in trichoscopy and scalp biopsy but uHFUS was able to detect pathological findings associated with hair cycle, inflammation, fibrosis, and subcutaneous abnormalities, which are hardly assessable by trichoscopy., Conclusion: The findings of this study highlighted usefulness of uHFUS in diagnosing hair disorders, while overcoming the weaknesses and limitations of other diagnostic tools., Competing Interests: Declaration of Competing Interest M.K. is a scientific advisor for Janssen Pharmaceutical K.K. MO is a scientific advisor for Eli Lilly Japan, Pfizer Japan Inc., Janssen Pharmaceutical K.K., Taisho Pharmaceutical Co., and RHOTO Pharmaceutical Co. and receiving research grants not related to this study from Shiseido Co. and Sun Pharma Japan Ltd. FS. F is a consultant and a scientific advisor for VisualSonics. He is receiving a research grant as P.I. from VisualSonics. The remaining authors state no conflict of interest., (Copyright © 2021 Japanese Society for Investigative Dermatology. Published by Elsevier B.V. All rights reserved.)

Hair follicle neoplasms occur in many different species, including humans. In domestic animals, they are most common in dogs. Most hair follicle tumors are benign, but malignant neoplasms can also occur. To diagnose hair follicle neoplasms, a thorough knowledge of follicular anatomy is important, given that follicular tumors are classified according to the differentiation pattern seen in the corresponding part of the normal hair follicle. This review focuses on the key diagnostic features of hair follicle tumors and follicular cysts in dogs and cats.

In this review, we propose that telomere length dynamics play an important but underinvestigated role in the biology of the hair follicle (HF), a prototypic, cyclically remodeled miniorgan that shows an intriguing aging pattern in humans. Whereas the HF pigmentary unit ages quickly, its epithelial stem cell (ESC) component and regenerative capacity are surprisingly aging resistant. Telomerase-deficient mice with short telomeres display an aging phenotype of hair graying and hair loss that is attributed to impaired HF ESC mobilization. Yet, it remains unclear whether the function of telomerase and telomeres in murine HF biology translate to the human system. Therefore, we propose new directions for future telomere research of the human HF. Such research may guide the development of novel treatments for selected disorders of human hair growth or pigmentation (e.g., chemotherapy-induced alopecia, telogen effluvium, androgenetic alopecia, cicatricial alopecia, graying). It might also increase the understanding of the global role of telomeres in aging-related human disease., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)

Pilomatricoma, also known as calcifying epithelioma of Malherbe, is a common benign skin adnexal tumor with differentiation toward hair cortex cells, commonly seen in head and neck region of children. It is usually solitary. Herein, we present a rare case of pilomatricoma with extensive osseous metaplasia as a thigh swelling in an adult female, considered clinically to be a sebaceous cyst. Florid osseous metaplasia is extremely rare in cases of pilomatricoma. To date, fewer than 10 cases of pilomatricoma with extensive osseous metaplasia at different sites have been reported in the English literature., (© 2020 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Pilomatricoma, a benign skin appendage tumor, also known as calcifying epithelioma, consists of islands of epithelial cells histologically that contain anucleated cells in the center surrounded by basophilic cells and partial calcification. Sporadic pilomatricomas commonly have somatic mutations in the gene CTNNB1, but causative genes from germline and the underlying pathophysiology are unclear. In this study, we identified a germline missense variant of PLCD1 encoding PLCδ1, c.1186G>A (p.Glu396Lys), in a large Chinese family with autosomal dominant multiple pilomatricomas. Phospholipase C, a key enzyme playing critical roles in intracellular signal transduction, is essential for epidermal barrier integrity. The p.Glu396Lys variant increased the enzymatic activity of PLCδ1, leading to protein kinase C/protein kinase D/extracellular signal-regulated kinase1/2 pathway activation and TPRV6 channel closure, which not only resulted in excessive proliferation of keratinocytes in vitro and in vivo but also induced local accumulation of calcium in the pilomatricoma-like tumor that developed spontaneously in the skin of Plcd1 E396K/E396K mice. Our results implicate this p.Glu396Lys variant of PLCD1 from germline leading to gain-of-function of PLCδ1 as a causative genetic defect in familial multiple pilomatricomas., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)

A classic pilomatricoma, which usually presents with an asymptomatic, solitary, firm, subcutaneous nodule in the head, neck, or extremities of the paediatric population, is easily diagnosed based on its characteristic clinical and histopathological features. However, its variants often pose particular diagnostic challenges to clinicians due to their rarity and diverse clinicopathological features. We present a new pseudocystic variant, manifesting as solid lesions floating in a fluid-filled sac., (© 2020 The Australasian College of Dermatologists.)

Pilomatrixoma is a benign subcutaneous tumour arising from the sebaceous glands. Mutation in the CTNNB1 gene is seen, suggesting beta-catenin misregulation may be the cause of pilomatrixoma. The preoperative diagnosis may be improved by the awareness of the fact that pilomatrixoma is a common and benign skin tumour of the head and neck region. It presents as a well-defined mass, which may be firm to hard in consistency, usually attached to the skin, but not to the underlying tissue. The colour of overlying skin appears a reddish-brown tinge, indicating that it could be a case of pilomatrixoma. Here, we report a case of pilomatrixoma of the cheek in a woman along with the CT findings and histopathological appearances. Dental surgeons should consider it as one of the differential diagnosis in superficial head and neck swelling with calcification., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2020. No commercial re-use. See rights and permissions. Published by BMJ.)

It is an indisputable fact that obesity is associated with a series of health problems. One important hallmark of obesity is excessive accumulation of lipids in the adipocyte, especially triglyceride (TG). Currently, the adipocyte has been considered not only as a huge repository of excess energy in the form of fat but also as an important source of multiple hormones and cytokines called adipokines. In obesity, the adipocyte is dysfunctional with excessive production and secretion of pro-inflammatory adipokines, such as tumor necrosis factor α (TNF-α), interleukin 6 (IL-6), and leptin. On the other hand, accumulating evidence has shown that leptin plays a vital role in stimulating angiogenesis, controlling lipid metabolism, and modulating the production of pro-inflammatory cytokines. Furthermore, the various activities of leptin are related to the wide distribution of leptin receptors. Notably, it has been reported that enhanced leptin levels and dysfunction of the leptin signaling pathway can influence diverse skin diseases. Recently, several studies revealed the roles of leptin in wound healing, the hair cycle, and the pathogenic development of skin diseases, such as psoriasis, lupus erythematosus, and dermatological cancers. However, the exact mechanisms of leptin in modulating the dermatological diseases are still under investigation. Therefore, in the present review, we summarized the regulatory roles of leptin in the pathological progression of diverse diseases of skin and skin appendages. Furthermore, we also provided evidence to elucidate the complicated relationship between leptin and different dermatological diseases, such as systemic lupus erythematosus (SLE), psoriasis, hidradenitis suppurativa, and some skin tumors., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Su, Cheng and Chang.)

Gray hair is a visible sign of tissue degeneration during aging. Graying is attributed to dysfunction of melanocyte stem cells (McSCs) that results in depletion of their melanin-producing progeny. This non-lethal phenotype makes the hair follicle and its pigment system an attractive model for investigating mechanisms that contribute to tissue aging and therapeutic strategies to combat this process. One potential combination therapeutic is RT1640, which is comprised of two drugs that are known to stimulate hair growth (cyclosporine A [CsA] and minoxidil), along with RT175, a non-immunosuppressive immunophilin ligand that is implicated in tissue regeneration. Using the ionizing radiation-induced acute mouse model of hair graying, we demonstrate that RT1640, over CsA alone, promotes regeneration of the hair pigment system during and following treatment. In non-irradiated mice, RT1640 is also physiologically active and successfully speeds hair growth and expands the McSC pool. It appears that this effect relies on the combined activities of the three drugs within RT1640 to simultaneously activate hair growth and McSCs as RT175 alone was insufficient to induce hair cycling in vivo, yet sufficient to drive the upregulation of the melanogenic program in vitro. This study sets the stage for further investigation into RT1640 and its components in McSC biology and, ultimately, melanocyte hypopigmentary disorders associated with disease and aging., (© 2020 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Drug-induced changes of hair and nails have been observed with a variety of different pharmaceutical agents, both topical and systemic. These compounds or their metabolites may interfere with hair cycling and texture, nail matrix, nail bed, nail folds, and microvasculature. Phototoxic reactions may also occur. Before initiating treatment, physicians and patients should be aware of possible adverse events to hair and nails and should be aware of the preventive measures, if available, as quality of life can be reduced, and adherence and compliance to treatment may be impaired., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Background: Malignant pilomatricoma (MP) is a rare cancer of the hair matrix with only a few cases reported in literature. Given the rarity of this cancer and the lack of relevant genetic data, very little is known about the nature of the molecular pathophysiology except the involvement of the Catenin Beta 1 (CTNNB1)/Wnt/β-catenin signaling pathway in some cases., Materials and Methods: We describe the whole-exome genomic profiling of four samples from two patients: 1) an MP from patient I, 2) a coexisting benign pilomatricoma (BP) from patient I, 3) a BP from an age and location-matched control patient II, and 4) normal skin tissue from patient II., Results: We detected a pathogenic somatic missense mutation in fibroblast growth factor receptor 4 (FGFR4) (c.1162G>A, p. Gly388Arg) in MP and coexisting BP in patient I, whereas the control BP harbored the classical CTNNB1 mutant., Conclusion: This study, the first comparative analysis of benign and MP through whole-exome analysis, identified a novel oncogenic mutation in FGFR4., (Copyright© 2020, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.)

Pilomatricoma usually contains a mutation in CTNNB1 that encodes β-catenin (BC). It also shows nuclear accumulation of BC protein, which plays an important role in tumorigenesis of pilomatricoma. In vitro studies have indicated that mutant BC protein is unphosphorylated and shows nuclear accumulation, but this theory has not been confirmed in various tumors with CTNNB1 mutation. We examined immunohistochemical localization of phosphorylated BC (pBC) and unphosphorylated BC (npBC) with regard to the modes of cell death or differentiation in 25 cases of pilomatricoma. As for the component showing shadow cell differentiation, BC was detected in cytoplasm/nucleus and along cell membrane in basaloid cells, whereas only in the latter in transitional cells in all cases. Meanwhile, npBC was localized along cell membrane of transitional cells, but not in basaloid cells, nor in nucleus of any components. The components with squamous differentiation also revealed the staining patterns similar to those seen in shadow cell differentiation in some cases. pBC was found in some cell fragments in the amorphous debris containing apoptotic bodies among shadow cell nests. These results suggested that npBC plays an important role in cell adhesion during differentiation and that pBC expression is associated with apoptosis of basaloid cells in pilomatricoma. BC accumulated in the nucleus was not immunoreactive for npBC possibly due to post-translational modification or conformational changes that resulted in loss of or masked antigenicity when BC is assumed to be unphosphorylated.